Alum is a natural mineral with antiseptic and astringent properties. For centuries, alum has been used as a hemostatic and for alleviating razor burn and skin irritations. After shaving, the alum block is first wetted and then rubbed gently over any affected skin areas. It is also a popular aftershave or deodorant. Alum doesn't contain preservatives, colorants or fragrances. It is hypoallergenic, cost-effective and extremely economical.